As science and technology advance in recent years, a single electronic device can achieve more and more diversified functions. For example, electronic components which have functions like printing, audio/video display, touch input, audio, wireless communication, or others function corresponding to itself are integrated into a single multifunctional electronic device. Hence, a good power management is very important to ensure an electronic device work normally under a stable power supply or to even achieve the goal of energy conservation.
For example, these days logistics industry often adopts an appropriative electronic point-of-sale system (POS) to manage or to assist selling commercial products at stores. It is usual that the POS can be applied to cash registers and interactive selling systems (or interactive selling machine such as ibon and FamiPort).
After the standard of barcodes was established in 1970s, manufacturers print a barcode on a product before it leaving the factory. It is one of application for the POS system that a store keeper can use barcodes to manage goods. Recently, the POS informative system gradually functions like a personal computer. The structure of a personal computer is utilized to do with files, manage stock and customer information, swipe cards, and validate data et cetera.
In the present POS system, it has printing modules (such as a thermal printer) for printing receipts or invoices, wireless communication modules for transmitting the information of goods and orders, displayers, touch panels, audio players, processors, barcode identification modules and other essential electronic components together.
Practically, a power supply used in an electronic device (such as a POS system) generally has a maximum power (such as 350 W˜400 W for an electronic device under a computer architecture) to meet the power-saving and safety requirements. In a system with a constant voltage, if the various components (e.g., a printing module, a wireless communication module, an audio player, etc.) in an electronic device are activated at the same time, then the total load current of the electronic device are increased instantaneously. In this moment, if the inrush current of the total loads exceeds the maximum, the electronic device may be crushed or even damaged permanently.
Therefore, the present invention offers a portable electronic device to solve the problem as mentioned previously.